IMO, I would lower the light intensity a bit since they do look a tad sunburnt.
Nepenthes (at least the ones you grow; N.ampullaria, etc.), originate in shaded environments.
I should get you a picture of the other cultures. They’re developing roots at a young-age and the medium/plants are exactly the same. These are seed grown so it’s likely genetics in play.
Have you ever tried de-flasking unrooted plants? Always curious how that would turn out.